Edge radius for sharp edges to look and feel 'good'

Quick question... I'm preparing a part for printing with colored strong&flexible. The part is going to have 'sharp' edges, and I currently have them designed with 90 degree bends and no radius to ease the edge. I have a feeling those crisp edges might end up feeling sharp and gritty... is this true? Is there a small radius you could recommend to keep the edges looking crisp (for cosmetic reasons), but also remove any harsh "feeling" to the edges? Or maybe there's just some magic-ish number you would recommend just works best in 3d applications? Cheeeeeeers!